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38 APRIL 2016 | EMSWORLD.com Different firefighting operations require specific types of protective equipment— structural, aircraft, wildland and, of course, hazmat. Protection from one hazard may not provide protection from another. A protective ensemble is designed to cover every part of a firefighter's body during any type of movement, while also preventing heat from being transferred from a fire to the body. Because turnout gear is designed to prevent heat from enter- ing the body, a problem is that it also pre- vents heat from leaving the body. Normally, the body sweats to expel excess heat and regulate body temperature. Turnout gear may prevent cooling by trapping excess heat and moisture next to the body, caus- ing an increase in core temperature and a consequent increase in respiratory and heart rate. Design Turnout coats and pants are comprised of three distinct layers: an inner thermal liner, a middle moisture barrier and an outer f lame-resistant shell. The inner- most thermal liner is considered the most important component because it has the greatest impact on protection from heat. In fact, the thermal liner and moisture barrier together represent about 75% of the thermal protection. Thermal liners, typically made from Kevlar and Nomex, are designed to trap air between layers of material. Both are copyrighted materials created by DuPont in the 1960s. The middle moisture barrier, made of the DuPont product Nomex with a polytetra- fluoroethylene (PTFE) film, is designed to protect the wearer against water, chemicals and biological agents. This middle layer represents the most delicate of the three protective components. It's important that all turnout gear receive an individual inspection after each use, and an advanced inspection yearly or when routine inspec- tions indicate a problem, as specified in NFPA 1851, Standard on Selection, Care, and Maintenance of Protective Ensembles for Structural Fire Fighting and Proximity Fire Fighting. The first line of defense, the outer shell, is also constructed of Nomex and Kevlar. It aids in thermal protection, accounting for the remaining 25%. It protects the wearer and inner layers against flame, water, cuts and abrasions. Outer shells of turnout coats and pants may also use ripstop con- struction (Figure 2), a special reinforcing technique that makes material resistant to tearing and ripping. During weaving, thick reinforcement threads are interwo- ven at regular intervals—generally 0.2 to 0.3 inches—in a crosshatch pattern. Thin and lightweight ripstop fabrics may have a three-dimensional structure because the For More Information Circle 32 on Reader Service Card Figure 2